CSF RBC AND WBC DIFFERENTIAL

The CSF provides a physiologic system to supply nutrients to the central nervous tissue, to remove metabolic wastes, and to produce a mechanical barrier to cushion the brain and spinal cord against trauma. Approximately 20 ml of fluid are produced every hour in the choroid plexuses and reabsorbed by the arachnoid villi to maintain a total volume of 90-150 ml in adults and 10-60 ml in neonates. The usual examination of the CSF specimen includes several observations such as CSF appearance (color, clarity, and clot formation), manual cell count, and a cytospin slide for differential count. Because cells are more dense than its suspending fluid, cytocentrifugation forces the cells from the suspension in a sample chamber onto a slide with the fluid absorbed by the blotter. The result is a monolayer of well-displayed cells grouped within an area. With this preliminary laboratory information and clinical observations, the physician can begin treatment without having to wait for the microbiology reports.